Bus blast was "no doubt" product of an attack, police say
An explosive device was placed on the back of a bus, which went up in flames, HaLevi said.

(CNN) A Monday bus blast in Jerusalem that injured at least 21 people was a deliberate attack, according to Israeli police officials.
A spokesperson for Jerusalem Mayor Nir Barkat, however, stayed away from labeling it an attack, saying the cause of the explosion remains ongoing.
Police initially reported it was a terror attack but then backtracked, saying all possibilities are under investigation.
Though Jerusalem District Police Commander Yoram HaLevi told CNN affiliate Channel 2 Israel "there was no doubt" it was an attack, it’s unclear whether the attacks was linked to terror groups.

The bus was attacked Monday in South Jerusalem, on Moshe Baram Street, injuring passengers on a separate but adjacent bus, Israeli police said

The explosive device was on the back of the bus, HaLevi said. Video from the Israel Fire and Rescue Authority showed the bus engulfed in flames.
Israel police spokesman Micky Rosenfeld updated the injury toll to 21 Monday night.